1. Field of the Invention
This invention relates to a pipe hanger and more particularly to a pair of clamp members coated with a moisture resistant polymeric material and connected at one end to a structural element and at an opposite end to each other by a fastening element encapsulated within a moisture resistant seal.
2. Description of the Prior Art
Pipe clamps are well known in the art for securing a conduit, pipe or the like to a structural element, such as a beam member, a U-shaped channel, a cable tray, or the like. Typical of the known pipe hangers are the arrangements disclosed in the following U.S. Pat. Nos. 2,375,513; 2,846,169; 3,226,069; 3,417,951; 3,527,432; 3,547,385; and 3,650,499. These devices include a pair of complementary clamping plates each having a curved configuration with one end notched to form a shoulder to engage the flange of a supporting channel and an opposite end portion having a bore for receiving a bolt to draw together the clamp members to securely grip the conduit.
One of the disadvantages of the known pipe hangers is that the clamp plates, as well as the threaded connection of the bolt in the threaded bores of the clamp plates, are subject to corrosive damage when exposed to a corrosive environment. In many applications, the clamp plates are located in an environment where moisture and other chemicals can damage the substrate of the plates and "freeze" the threaded connection of the bolt to the plates. Eventually, the clamp plates require maintenance or replacement, which can be difficult when the bolt becomes "frozen" on the plates.
It is also well known in the art, as disclosed in U.S. Pat. Nos. 3,724,706; 3,784,236; 3,799,584; and 4,316,690, to coat components of an assembly that must be capable of efficient assembly and disassembly in a corrosive environment. These devices include a moisture resistant, insulating, resilient polymeric coating, such as polyvinylchloride (PVC) applied to the exposed metal substrate. It is also known, as disclosed in these patents, to provide male and female interconnecting elements coated with a polymeric material to form a moisture resistant seal therearound. This prevents moisture from entering the point of engagement, for example, of a nut on a threaded bolt, to prevent the nut from "freezing" on the bolt.
While it is known to coat the components of interconnecting members with a moisture resistant, polymeric coating, the threaded surfaces of the members are generally exposed prior to assembly of the components in the field. For example, even though portions of nuts and bolts are coated, the threaded portions are exposed to the atmosphere and to the effects of moisture prior to assembly.
It is also known to apply a moisture resistant, polymeric material by brush coating exposed connecting elements, such as nuts and bolts. However, a moisture resistant coating applied in this manner to threaded connections of fastening elements is not always successful in preventing corrosion in a deleterious atmosphere. It has been found in most cases that brush coating of a polymeric material, after installation, will not deter the accumulated effects of the corrosive atmosphere prior to the application of the coating. Furthermore, if improper attention is given to the brushing application of the polymeric material to the exposed threads, an insufficient coating thickness to prevent corrosion may result.
Therefore, there is need for a pipe hanger and the like operable in a corrosive environment to resist corrosive damage to the elements of the pipe hanger prior to installation and after installation and usable for a range of pipe diameters.